A general module structure in a solar cell includes a glass front sheet, an ethylene-vinylene acetate (EVA) copolymer encapsulate film, a solar cell, another EVA copolymer encapsulate film, and a back sheet from top to bottom. The EVA copolymer encapsulate films may fasten to the solar cell, connect to circuit lines, insulate and protect the solar cell, and maintain solar cell performance after long-term use. The back sheet may provide electrical insulation, thermal resistance, and moisture resistance to expand the lifetime of the module structure of the solar cell.
Existing back sheets are composed of fluorinated resin films and polyethylene terephthalate (PET) film. The fluorinated resin films are usually coated or laminated on two sides of the PET film to meet the requirements of moisture resistance and the like. In addition, the adhesive coating layer is utilized to provide sufficient adhesion between the fluorinated resin film and the EVA copolymer encapsulate film.
Accordingly, developing a novel back sheet structure is called for.